Cushioning device for electric motors



Jan. 12,1943.

c. H. DUFFY CUSHIONING DEVICE FOR ELECTRIC MOTORS Filed May 3, 1941 Patented Jan. 12, 1943 UNITED STATES PATENT OFFICE CUSHIONIVNG DEVICE FOR ELECTRIC MOTORS (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 14 Claims.

The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon in accordance with the provisions of the act of April 30, 1928 (Ch. 460, 45 Stat. L. 467).

This invention relates to devices for cushioning or absorbing the shock due to the end-play of shafts, and is particularly adapted for use on the rotor or armature shafts of electric motors, though it will appear from the following specification taken in connection with the accompanying drawing that the device is equally applicable to shafts in general.

Referring to the drawing:

Figure 1 is a side elevation of the rotor and shaft of an electric motor in its end bearings and illustrating the device in operative position on both ends of the rotor shaft.

Figure 2 is a side elevation of the square bushing employed in the device.

Figure 3 is an end elevation of the same.

Figure 4 is an edge elevation of the spring tension-washer assembly.

Figure 5 is a front elevation of the same.

Figure 6 is an end elevation of the round tubular spacer bushing.

Figure 7 is an end elevation of a modified form illustrating the tubular bushing as being square.

Figure 8 is a side elevation of a modified form of the square bushing shown in Figure 2.

Figure 9 is a side elevation of a similar square bushing as used in the modified assembly shown in Figure 10, and

Figure 10 is a side elevation of a modification of the device shown in Figure 1.

Like numerals of reference indicate the same parts throughout the several figures, in which,

I indicates the rotor or armature of an electric motor, 2 and 3 indicate the end portions of the rotor or armature shaft 4, and 5 and 6 indicate the shaft bearings.

1 indicates the shock cushioning or absorbing device, which includes the square bushing 8; tension washer assembly 9; tubular spacer bushing l0 and thrust washer l I.

In practice, the bearings 5 and 6 are suitably supported in the motor frame or housing in any approved manner. Prior to mounting the rotor or armature shaft in its bearings 5 and 6, a square bushing 8 having a bore 8 of a size to provide a slight press fit on the shaft 4, is positioned on each end portion 2 and 3 of said shaft, and in the example shown in the drawing, placed directly against the sides of the rotor I. These square bushings 8 are of such length that the outer ends thereof are spaced from the shaft bearings 5 and 6, as shown in the drawing. The spring-tensicn-washer assembly 9 which includes two flat washers 9 of suitable material, and a central intermediate spring-tension-washer 9", either cupped as shown, or of any other appropriate or conventional form, and of any approved spring material, is placed between the two fiat washers 9', as shown in Figure 4.

These washers 9 and. 9" are each provided with square holes 9", so that they may freely move longitudinally over the square bushing 8 but will not rotate thereon. The tubular spacer bushing H), which may be either round or square, is provided with a bore I0 sufficient to permit the spacer to freely pass over the end of the square bushing 8 and have free longitudinal movement with respect to the square bushing 8. The thrust washer I I is then placed on the shaft and against the outer end of the spacer bushing 10, so that the inner end of the spacer bushing l0 bears against the outermost flat washer 3' of the spring-tension-washer assembly while the outer end of the spacer bushing l0 abuts the thrust washer I l, as shown in Figure 1.

In operation the device is applied to each end 2 and 3 of the shaft 4, with the thrust washers H against the shaft bearings 5 and 6, as in the example shown. Longitudinal movement (endplay) of the shaft in either direction will cause one or the other of the spring-tension-washers 9" to be compressed between its contacting flat washers 9' and thus cushion or absorb the shock of such longitudinal shaft movement (end-play) which would otherwise occur, and which usually results in a rapid, objectionable hammering noise.

It will be seen that the function of the square bushings 8 pressed on the shaft 4 and of the square holes in the spring-tension-washer assembly 9 is to insure rotation of the spring-tensionwasher assembly with the shaft, and thus prevent any cutting action on or injury to the shaft which usually occurs when a spring-tension-washer is mounted directly on the shaft and relative rotation between shaft and spring-tension-washer is permitted. An additional advantage resulting from this construction, is that wear on the tension washer assembly which would result from relative rotation of the washers is entirely eliminated.

If the spacer bushing is square, as shown, this bushing is also caused to rotate with the shaft and tension-washer-assembly 9 so that all relative rotation is localized at the thrust washer,

be understood that the drawing merely i1lustrated one example of the application of the device to a shaft which is subject to objectionableend-play. In other applications the square bushing 8 and spring-tension-washer assembly Smay" contact any suitable abutment on a shaft, while the thrust washer Il may contact any suitableabutment on the frame or other stationary struc-' ture to which the shaft is applied.

It is also apparent that any desired number of conventional thin fiat washers may be applied in connection with the device in order to adjust the length of the same to any particular condition without departing from the spirit of the invention.

1 For such shafts as do not have a convenient abutment against which the square bushing and spring-tensicn-washer assembly may bear, the square bushing may itself be provided with an abutment 3" as shown in Figure 8. In such applications the squarebushing' 8 with its abutment is pressed on theshaft to a predetermined position, the spring-tension-washer assembly 9 is placed on the square-bushing and against the abutment 8" on thesquare bushing B, and the spacer bushing wand thrust washer l l are assembled in the same relative positionsas shown in Figure 1.

In the modified-example shown in Figure 10, which illustrates'theuse of the modified form of square bushing 8, shown in Figure 8, pressed on the shaft to a predetermined position to provide a shoulder abutment 8" for the springtension-washer assembly 6. In this example, there is also shown abutting the outer end of the square spacer bushing; i 5, a-shallow square bushing !2 having a shoulder abutment I2 similar to the modifiedsquare bushing 8-and its shoulder abutment 8" except that the bore of this square bushing l2 is of a size to permit free longitudinal movement on the shaft, while abutting the flanged abutment I2 of this square bushing I2 is the thrust washer H.

Inoperation, thesquare spacer bushing l0 extends over the end of the square bushing 8- and abuts against the tension washer assembly 9, also extends over the square bushing I2 and abuts against its flanged abutment I2 so that every element of the assembly rotates with the shaft except the thrust washer. H, and all relative rotation is positively localized at the thrust washer H.

What I claim is:

1; A device for absorbing or cushioning the end-play of the shafts of lectric motors and the like, which includes, in' combination with the shaft provided with an abutment thereon, a square bushing having a boresmall enough to provide a press fit on the shaft to insure rotation of thesquare bushing with the shaft, a spring tension-washer assembly mounted on the square bushing and against the abutment on the shaft, the spring-tension washer assembly including two flat washers and an" intermediate springtension washeradapted for compression between the two flatiwashersofthev assembly, all of the washers of the spring-tension washer assembly being provided with square holes slightly larger than the square bushing to insure rotation thereof with the square bushing and provide free longitudinal movement thereon, a thrust washer on the shaft and a square tubular spacer bushing having its hole slightly larger than the first mentioned square bushing and positioned over the end of the first mentioned square bushing and between the spring washer assembly and the thrust washer.

2. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft provided with an abutment thereon, a

square bushing having a bore small enough to provide a press fit on the shaft to insure rotation of the square bushing with the shaft, a spring-tension washer assembly mounted on the square bushing and against the abutment on the shaft, the spring-tension washer assembly including a spring tension washer and two flat washers, the flatwashers'being provided with square holes large enough to permit longitudinal movement thereof on'the square bushing and to insure rotation'there'of with the square bushing, a thrust washer on the shaft and a tubular spacer bushing having a hole large enough to freely pass over the end of the square bushing and between the spring-tension washer assembly and the thrust Washer.

3. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like which includes, in combination with the shaft, a square bushing mounted on the shaft, a spring tension washer mounted on the square bushing, and provided with a square'hole large enough to permit longitudinal movement thereof on the square bushing and to insure rotation thereof with the square bushing, a'th'rust washer and spacing means between the spring tension washer and the thrust washer.

4. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft, a bushing 'mountedonthe shaft; a springtension washer assembly mounted on the bushing, the assembly including a spring-tension washer and two fiat washers, said washers having holes large enough to permit longitudinal movementof the washerson the bushing, the said bushing and the holes of the flat washers being shaped to interengagean'd insure rotation of the flat washers with the said bushing, a thr'ust washer and means for spacing the spring-tension Washer assembly fromthe thrust Washer.

5.- A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with a rotatable and longitudinally movable shaft, a bushing mounted on the shaft, a spring-tension washer mounted on the bushing, the said bushing and thehole in the spring-tension washer being shaped to interengage and insure rotation of'the washer with the said bushing, a thrust washer remote from the bushingand mounted on the shaft, and means for spacing the: spring tension washer from the thrust washer.

6. A device for absorbing or cushioning the end-play of the shaftsof electric motors and the like, which includes; in combination with a rotatable and longitudinally movable shaft, a bushing mounted on the shaft, a spring-tension washer assembly mounted on the bushing, a thrust washer remote from the bushing and mounted on the shaft, and means for spacing the spring-tension washer assembly from the thrust washer.

7. A device for cushioning or absorbing the endplay of the shafts of electric motors and the like, which includes, in combination with the shaft, a square bushing having a bore small enough to provide a press fit on the shaft to insure rotation of the square bushing with the shaft, an abutment on the square bushing, a spring-tension washer assembly mounted on the square bushing and against the abutment thereon, the springtension washer assembly including two flat washers and an intermediate spring-tension washer adapted for compression between the two fiat washers of the assembly, all of the washer of the spring-tension washer assembly being provided with square holes slightly larger than the square bushing to insure rotation thereof with the square bushing and provide free longitudinal movement thereon, a thrust washer on the shaft, a square bushing adjacent the thrust washer, having a bore larger than the shaft to permit free longitudinal movement thereof on the shaft, an abutment on the square bushing, and a square tubular spacer bushing having its hole slightly larger than the first mentioned square bushing and positioned over the first mentioned square bushing and over the square bushing adjacent the thrust washer and between the spring washer assembly and the abutment on the square bushing adjacent the thrust washer.

8. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft, a square bushing having a bore small enough to provide a press fit on the shaft to insure rotation of the square bushing with the shaft, an abutment on the square bushing, a spring tension washer assembly mounted on the square bushing and against the abutment thereon, the spring-tension washer assembly including a spring-tension washer and two fiat washers, the flat washers being provided with square holes large enough to permit longitudinal movement thereof on the square bushing and to insure rotation thereof with the square bushing, a thrust washer on the shaft, a square bushing adjacent the thrust washer and having a bore large enough to permit free longitudinal movement thereof on the shaft, an abutment on the last mentioned square bushing and a tubular spacer bushing having a hole large enough to freely pass over the first mentioned square bushing and disposed between the spring tension washer assembly and the abutment on the last mentioned square bushmg.

9. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft, a square bushing mounted on the shaft, an abutment on the square bushing, a spring tension washer mounted on the square bushing and provided with a square hole large enough to permit longitudinal movement thereof on the square bushing and to insure rotation thereof with the square bushing, a thrust washer on the shaft, a square bushing adjacent the thrust washer and having a bore large enough to permit longitudinal movement thereof on the shaft, an abutment on the last mentioned square bushing, and spacing means between the spring tension washer and the abutment on the last mentioned square bushmg.

10. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft, a bushing mounted on the shaft, an abutment on the bushing, a spring-tension washer assembly mounted on the bushing, the assembly including a spring tension washer and two fiat washers, said washers having holes large enough to permit longitudinal movement of the washers on the bushing, the said bushing and the holes of the fiat washers being shaped to interengage and insure rotation of the fiat washers with the said bushing, a thrust washer, a bushing on the shaft adjacent the thrust washer and provided with an abutment, and means for spacing the spring-tension washer assembly from the thrust washer.

11. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft, a bushing fixed on the shaft and rotatable therewith, an abutment on the bushing, a spring tension washer mounted on the bushing and rotatable with the bushing and the shaft, the said bushing and the hole in the spring tension washer being shaped to interengage and insure rotation of the washer with the said bushing a thrust washer and means for spacing the spring tension washer from the thrust washer.

12. A device for absorbing or cushioning the end-play of the shafts of electric motors and. the like, which includes, in combination with the shaft, a bushing fixed on the shaft and rotatable therewith, an abutment on the bushing, a springtension washer assembly mounted on the bushing, a thrust washer, and means for spacing the spring-tension washer assembly from the thrust washer.

13. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft, a bushing fixed on the shaft so as to insure rotation of the bushing with the shaft, and to prevent longitudinal movement of the bushing with respect to the shaft, a spring tension washer assembly mounted on the bushing and rotatable therewith, and means coacting with the spring washer assembly to cause compression of the spring tension washer of the assembly upon longitudinal movement of the shaft in one direction.

14. A device for absorbing or cushioning the end-play of the shafts of electric motors and the like, which includes, in combination with the shaft, a bushing fixed on the shaft so as to insure rotation of the bushing with the shaft, and to prevent longitudinal movement of the bushing with respect to the shaft, a spring tension washer mounted on the bushing and rotatable therewith, and means coacting with the spring-tension washer to cause the same to be compressed upon longitudinal movement of the shaft in one direction.

CHARLES HUGH DUFFY. 

